Sunday, July 23, 2017

Fukushima robot finds likely melted fuel

An underwater robot has captured images of deposits believed to be
melted nuclear fuel in a damaged reactor at Japan's crippled Fukushima
nuclear plant.

An underwater robot has captured images of massive deposits
believed to be melted nuclear fuel that are covering the floor of a
damaged reactor at Japan's crippled Fukushima nuclear plant.
Plant operator Tokyo Electric Power Co. said on Saturday solidified
lava-like rocks heaped up from the bottom inside of a main structure
called the pedestal that sits underneath the core inside the primary
containment vessel of Fukushima's Unit 3 reactor.
Experts believe the melted fuel fell to the chamber's bottom and is now submerged by radioactive water.
The robot on Friday spotted suspected debris of melted fuel for the
first time since the 2011 earthquake and tsunami destroyed the plant.
The three-day probe ends on Saturday.
Locating the fuel in each of the three wrecked reactors is crucial for the plant's decommissioning.

Lava-like rocks believed to be
melted nuclear fuel have been spotted inside Japan's stricken Fukushima
reactor by an underwater robot, the plant's operator said at the end of a
three-day inspection.
Large amounts of the solidified
lumps and deposit were spotted for the first time by the robot on the
floor of the primary containment vessel underneath the core of
Fukushima's No. 3 reactor, the Tokyo Electric Power Co (TEPCO) said.
"There
is a high possibility that the solidified objects are mixtures of
melted metal and fuel that fell from the vessel," a TEPCO spokesman
said, adding that the company was planning further analysis of the
images.
The three-day investigation using the small,
remote controlled underwater robot, which is about the size of a loaf of
bread, ended Saturday, the spokesman said.
TEPCO said
the images were the first "highly likely" sighting of melted fuel since
the 2011 disaster, when a massive undersea earthquake sent a huge wave
barrelling into Japan's northeast coast, killing more than 18,500
people, and sending three reactors into meltdown at the plant in the
worst such accident since Chernobyl in 1986.
Locating the fuel debris is a key part of the decommissioning process for the plant, which is expected to take decades.

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In February, TEPCO sent another robot into one of three damaged reactors where radiation levels have hit record highs.
But
the mission at the No. 2 reactor was aborted as the robot had
difficulty moving and could not reach its target destination beneath the
pressure vessel, through which nuclear fuel is believed to have melted.
The
Japanese government said in December that it expects total costs
including compensation, decommissioning and decontamination to reach
21.5 trillion yen ($192.5 billion) in a process likely to take at least
four decades as high radiation levels slow operations.Read more at http://www.channelnewsasia.com/news/asiapacific/robot-finds-possible-melted-fuel-inside-fukushima-reactor-9055632